"Do you like my desk?"
Translation:An toil leat an deasg agam?
It’s literally the desk at you or the desk by you (as in by your side). Scottish Gaelic does have proper possessive pronouns, but they are only used for inalienable possession (things that are integral part of yourself, like body parts, or are very close, family members, etc.), so you can say do mhàthair ‘your mother’, but rather an deasg agad and not
do dheasg for ‘your desk’.
The Possessives and syllabic structure or Ar n-Athair a tha air nèamh article on the Akerbeltz wiki explains it nicely.
The mo/do/ etc. possessives in gàidhlig are used primarily for things that cannot be easily lost. Things that are intrinsically part of you or or your life. So family (though there are some exceptions there), language, country, that sort of thing. For something so prosaic as a desk, no. It would not be used. Desks are interchangeable, you can get a new desk easily. It's just the desk that is at you or with you right now, but it could be a different one tomorrow. Also, mo lenites, so that would also be an issue even if a desk could use that possessive.